Refrigerated cargo carrying vehicles are commonly used to transport goods which must be maintained at less than ambient temperatures. For example, a refrigerated trailer pulled by a tractor is commonly used for this purpose.
The interior of a refrigerated trailer is commonly cooled by a refrigeration unit carried on the wall of the trailer. The refrigeration unit comprises various components, including a condenser, and the refrigeration unit is commonly housed within a metal enclosure which only partially encloses the unit. The enclosure is provided with an opening to receive outside air to cool the condenser.
The term "refrigeration unit" as used herein means the commonly used unit which provides cooling or heating to the interior of the cargo carrying vehicle. For example, when the trailer is used to haul certain goods in freezing temperatures, the refrigeration unit is employed as a heating unit. In this connection, it is known to utilize pivotal metal shutters for closing or partly closing the opening to improve the heating capacity of the refrigeration unit.
The metal enclosure described above is not aerodynamically configured, and thus it does not reduce the aerodynamic drag of the vehicle. It is known, however, to employ a wind deflector over the refrigeration unit to reduce the aerodynamic drag of the vehicle, and such an apparatus is disclosed in FitzGerald U.S. Pat. No. 4,310,192. The wind deflector of the FitzGerald patent has an opening confronting the condenser for supplying air to the refrigeration unit.
Although the aerodynamic wind deflector of the FitzGerald patent materially reduces the drag of the vehicle, it has been found that the air intake opening confronting the condenser inhibits the drag-reducing function of the wind deflector. The opening has also been found to be undesirable for other reasons in that it promotes noise pollution from the refrigeration unit, adversely affects stability of the trailer, and readily admits insects and debris to the refrigeration unit.